Сделайте полный анализ предложения(Past Progressive)
Альтернативные предложения,вопросительное,общее,отрицательное

He was doing his homework when mother entered the room.Общее (вопросительное): Was he doing his homework when mother entered the room?Альтернативное: Was he doing his homework or watching TV when mother entered the room?Отрицательное: He wasn't doing his homework when mother entered the room.